Calcutta: Police want to include "gang rape" in the charges against the two teachers of GD Birla Centre For Education arrested in November for an alleged sexual assault on a four-year-old student, the high court was intimated on Tuesday.

According to the submission by a government pleader, the police believe there are also grounds for a case against the former principal of the school for disclosing the identity of the girl in a letter to all parents.

Justice Debangsu Basak of the high court is monitoring the progress of the case.

The government pleader informed the judge that the police had petitioned a lower court in Alipore on Monday for permission to amend the charges against Abhishek Roy and Mohammad Mafisuddin, who are in jail custody.

The two physical education teachers have been charged with aggravated sexual assault under the Protection of Children from Sexual Offences (Pocso) Act. A separate case filed against former principal Sharmila Nath at Jadavpur police station on the basis of a complaint by the girl's father mentions cheating, causing disappearance of evidence and criminal conspiracy.

A senior officer in Lalbazar, the city police headquarters, said the police investigation had thrown up evidence to justify amending the original charges against the accused to include gang rape. "We petitioned the court on Monday to include Section 376D (gang rape) of the Indian Penal Code against the two teachers and Section 228A (disclosure of identity of the victim of rape) against Nath," he said.

Someone held guilty under Section 376D can be sentenced to life. The offence of disclosing the identity of a rape victim invites a maximum punishment of two years in jail.

Responding to a petition from the girl's father, Justice Basak had asked the state for a report on the progress of the investigation into the alleged sexual assault. The judge also directed the state to mention its stand on the father's demand for legal action against the former principal and teachers of the school for disclosing the name of his daughter.

The father alleged that the police were not probing the case properly. He demanded a CBI inquiry.

The government pleader said on Tuesday: "The court should initiate a trial against the accused teachers after charging them under section 376D. The court should also initiate proceedings against the ex-principal of GD Birla Centre for Education under Section 228A for disclosing the name of the victim."

The next hearing in Alipore court is scheduled for Wednesday. The high court will resume its hearing on January 19.